Q: Will shrubs like azalea, tea rose, and boxwood need less water if I prune them back by one-third?
A: A plant’s water use is affected by a host of factors. Age of leaves, vigor of root system, humidity, light level, and, of course, water availability, all come into play. I suppose your shrubs would use less water if you reduce their size by one-third but they will produce new, water hungry leaves and sprouts next spring. These would have to be removed regularly in order to maintain lower water use. I’m not so sure that pruning now will make your plants markedly more drought tolerant. Prune if they need shaping, but don’t think of pruning as a water saving technique.